I've done the
adjustable power mod for two Wingun revolvers, it's pretty easy. Skeletor basically hit the nail on the head: revolvers are fun but not terribly practical. The shells are fiddly and easy to lose. Most feel really solid but turn out to be made of shitty pot metal that will wear down and break: on one of the revolvers I modded the cylinder axis pin broke. I was able to replace it by tapping out the center of the cylinder and carefully filing down a machine screw that was about the right size and shape.
That said though, they are incredibly fun and though I wouldn't recommend one as a first pistol, they're definitely worth it for just messing around.